Prosthetic Surgical Aortic Valves Top Worst Outcomes List

U.K. registry shows valve series' performance for mortality, revision

Action Points

Prosthetic aortic valves implanted over the past 15 years in the U.K. were tied to varying levels of adverse events, with two valves in particular appearing to underperform the competition.

Note that the study suggests that routinely collected clinical registry data can be leveraged for evaluating performance of medical devices, even when this was not a primary goal of the data collection program.

Prosthetic aortic valves implanted over the past 15 years in the U.K. were tied to varying levels of adverse events, with two valves in particular appearing to underperform the competition, a postmarket registry study found.

The Sorin Mitroflow series was associated with increased risk of reintervention or death (Cox proportional hazards regression with random effects, known as a frailty term, 1.19, 95% prediction interval [PI] 1.09-1.31) and showed a low 10-year freedom from those events of 33.8% (95% PI 31.3%-36.5%).

A second group, the Sorin Biological series, shared similarly dismal hazards (frailty 1.18, 95% PI 1.06-1.32) and freedom from adverse events (41.4%, 95% PI 37.6%-45.6%), according to Joel Dunning, PhD, of James Cook University Hospital in Middlesbrough, England, and colleagues.

Non-Sorin biological valves exceeded both devices with a 47.2% 10-year freedom from events rate (95% I 46.2%-48.1%), the group showed in their study appearing in JAMA Internal Medicine. Hence, the two Sorin valve series "may warrant further investigation," the authors wrote.

"As Taylor noted about valve monitoring nearly 3-decades ago, 'overreaction is as inappropriate as complacency,'" the researchers cautioned, though. "Given the limitations of the study, the signals shown here should only serve as hypothesis generating and not misinterpreted as causal effects."

"The need for such postmarketing surveillance of medical devices was made clear by the Poly Implant Prothèse breast implant and other medical device scares, yet infrastructure is lacking. We have shown that a national clinical registry, linked to other routinely collected data, might be used to inform postmarket surveillance programs," Dunning's group wrote.

Central to the investigation was the National Health Service number, a unique identifier that links patient data across clinical registries. Across the Atlantic, the authors noted, strategic linking of complementary registries and data sources is also recommended by the U.S. Medical Device Registries Task Force.

Extensive record linking could be extended to using unique serial numbers of implanted devices "to improve ongoing research, augment clinical trial follow-up after completion, and to allow traceability in case of serious fault detection. The planned role out by the FDA of a unique device identification system integrated for use with electronic health records would allow scalable cross-specialty surveillance."

Ultimately, the researchers had a bone to pick with the length of observation required to parse through the device data: "We explored outcomes in prosthetic valves cross-sectionally using 15 years of data. Moving forward, this is not a suitable approach for postmarket device surveillance, which should be dynamic, providing regular updates, to achieve superiority over existing passive reporting mechanisms."

Better data-collecting measures may help to detect signals of underperforming devices earlier on, they reasoned.

"While the methodology applied here was relatively simplistic, what we have demonstrated is that routinely collected clinical registry data can be leveraged for evaluating performance of medical devices, even when this was not a primary goal of the data collection program. With some improvements to the data collection mechanisms, this messy real-world registry, or other registries, data could be analyzed using alternative platforms."

Dunning's group analyzed 54,866 surgical aortic valve replacement cases with or without coronary artery bypass grafting performed in hospitals in England and Wales that submitted data to the National Adult Cardiac Surgery Audit from 1998 to 2013.

Over a median follow-up of 4.1 years, there were 13,104 deaths and 723 reinterventions.

Among the limitations of the registry study are the relatively short follow-up -- given that valve failure likely occurs beyond 4.1 years -- and the improbable adjustment for all confounders, especially institutional effects. Dunning and colleagues also commented on the free-text input for valve model data, a potential source of coding errors by surgeons.

Dunning disclosed receiving proctoring fees from Cardica.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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